/Engine/Source/Runtime/Engine/Classes/Engine/Texture2DArray.h
In the editor this can potentially wait for texture builds to complete.
bool GetMipData ( int32 InFirstMipToLoad, [TArray](API\Runtime\Core\Containers\TArray)< [FUniqueBuffer](API\Runtime\Core\Memory\FUniqueBuffer), TInlineAllocator< MAX_TEXTURE_MIP_COUNT >> & OutMipData )